Alternating current (ac) machines (e.g., IPM machines) are extensively used in loaders, combines or other heavy equipment machinery vehicle electric drive because they provide a higher efficiency than direct current (dc) machines. Of the ac machines, an Interior Permanent Magnet (IPM) machine has high drive efficiency and a wider constant power operating range. An IPM machine controller also called an inverter, controls operation of the IPM machine. The controller produces ac control signals which are applied to the terminals of the IPM machine. Typically the controller controls the IPM machine based on information or a portion of information characterizing the IPM machine. At least part of the characterization refers to the operational model of the IPM machine that permits translation of input requests into desired operational output. For example, a desired output torque may be requested, and based on part of the characterization, the controller controls the IPM machine to deliver the desired torque.